title: The transmembrane domain of podoplanin is required for its association with lipid rafts and the induction of epithelial-mesenchymal transition.
abstract: Podoplanin is a transmembrane glycoprotein that is upregulated in cancer and was reported to induce an epithelial-mesenchymal transition (EMT) in MDCK cells. The promotion of EMT was dependent on podoplanin binding to ERM (ezrin, radixin, moesin) proteins through its cytoplasmic (CT) domain, which led to RhoA-associated kinase (ROCK)-dependent ERM phosphorylation. Using detergent-resistant membrane (DRM) assays, as well as transmembrane (TM) interactions and ganglioside GM1 binding, we present evidence supporting the localization of podoplanin in raft platforms important for cell signalling. Podoplanin mutant constructs harbouring a heterologous TM region or lacking the CT tail were unable to associate with DRMs, stimulate ERM phosphorylation and promote EMT or cell migration. Similar effects were observed upon disruption of a GXXXG motif within the TM domain, which is involved in podoplanin self-assembly. In contrast, deletion of the extracellular (EC) domain did not affect podoplanin DRM association. Together, these data suggest that both the CT and TM domains are required for podoplanin localization in raft platforms, and that this association appears to be necessary for podoplanin-mediated EMT and cell migration.
authors.affiliation: Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Fernández-Muñoz
authors.forename: María M
authors.initials: MM
authors.lastname: Yurrita
authors.forename: Ester
authors.initials: E
authors.lastname: Martín-Villar
authors.forename: Patricia
authors.initials: P
authors.lastname: Carrasco-Ramírez
authors.forename: Diego
authors.initials: D
authors.lastname: Megías
authors.forename: Jaime
authors.initials: J
authors.lastname: Renart
authors.forename: Miguel
authors.initials: M
authors.lastname: Quintanilla
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D000818:Animals; D002460:Cell Line; D004285:Dogs; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D051147:Ganglioside Galactosyltransferase / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D015398:Signal Transduction; D054460:rho-Associated Kinases / Q000378:metabolism; D000098853:Podoplanin
chemical_list: D051147:Ganglioside Galactosyltransferase; D008562:Membrane Glycoproteins; D054460:rho-Associated Kinases; C117468:PDPN protein, human; D000098853:Podoplanin